Single fan tray in a midplane architecture

ABSTRACT

A chassis may include a front section that contains a first electronic circuit board oriented in a first plane, a rear section that contains a second electronic circuit board oriented in a second plane, where the first plane and the second plane are substantially orthogonal, a midplane dividing the front and the rear sections, and a fan tray assembly including a plurality of fans to cool both the first electronic circuit board of the front section and the second electronic circuit board of the rear section.

BACKGROUND

Various schemes may be employed for cooling printed circuit boards(PCBs) (e.g., line cards) and other components within a chassis of adevice. In instances where a device includes orthogonally oriented PCBs(e.g., horizontal PCBs and vertical PCBs) in a midplane design, theremay be at least two fan systems. For example, there may be one fansystem to cool the horizontal PCBs and another fan system to cool thevertical PCBs. However, even when employing two fan systems, air flowmay not be evenly distributed and may not adequately cool a loadedchassis.

SUMMARY

According to one aspect, a chassis may include a front section thatcontains a first electronic circuit board oriented in a first plane, arear section that contains a second electronic circuit board oriented ina second plane, where the first plane and the second plane aresubstantially orthogonal, a midplane dividing the front and the rearsections, and a fan tray assembly including a plurality of fans to coolboth the first electronic circuit board of the front section and thesecond electronic circuit board of the rear section.

According to another aspect, a method for cooling a device having amidplane design. The method may include directing a first airflow havinga first direction to provide a second airflow having a second direction,the second direction being orthogonal to the first direction, cooling,via the second airflow, a first electronic circuit board of the device,the first electronic circuit board being orthogonal to the midplane,redirecting the second airflow to provide a third airflow having a thirddirection, the third direction being orthogonal to the second direction,redirecting the third airflow to provide a fourth airflow having afourth direction, the fourth direction being orthogonal to the thirddirection, and cooling, via the fourth airflow, a second electroniccircuit board of the device.

According to still another aspect, a device may include a first array ofcircuit boards oriented in a first direction in a first compartment of achassis, a second array of circuit boards oriented in a second directionin a second compartment of the chassis, the second direction beingdifferent than the first direction, a midplane connecting one or morecircuit boards of the first array of the array of circuit boards withone or more circuit boards of the second array of circuit boards, and afan tray assembly having a plurality of fans disposed on a plane of thefirst compartment to cool both the first array of circuit boards and thesecond array of circuit boards.

According to yet another aspect, a device may include a first pluralityof circuit boards oriented in a horizontal direction, a second pluralityof circuit boards oriented in a vertical direction, a verticallyoriented midplane providing a connection between one or more circuitboards of the first plurality of circuit boards and one or more circuitboards of the second plurality of circuit boards, and a fan systemoriented on a plane that is parallel to the second plurality of circuitboards to cool both the first plurality of circuit boards and the secondplurality of circuit boards.

According to still another aspect, a device may include a midplaneconnecting a first circuit board oriented orthogonal to a second circuitboard, a chassis, and a cooling mechanism oriented on a planecorresponding to a side of the chassis, where the cooling mechanismpulls air to cool both the first circuit board and the second circuitboard.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate one or more embodiments describedherein and, together with the description, explain aspects of theinvention. In the drawings:

FIG. 1 is a diagram illustrating concepts described herein;

FIG. 2 is a diagram illustrating an exemplary device that may operateaccording to the concepts described herein;

FIG. 3 is a diagram illustrating an exemplary baffle that may correspondto the baffle depicted in FIG. 2;

FIGS. 4 and 5 are diagrams illustrating exemplary airflow patternsassociated with the concepts described herein; and

FIG. 6 is a flow diagram illustrating a process that may be associatedwith the concepts described herein.

DETAILED DESCRIPTION

The following detailed description refers to the accompanying drawings.The same reference numbers in different drawings may identify the sameor similar elements.

Spatially relative terms, such as “horizontal,” “vertical,” “front,” and“rear” and the like, may be used herein for ease of description todescribe an element or the element's relationship to another element asillustrated in the figures. Thus, these terms do not necessarily haveonly one operational meaning and are not intended to be limiting. Thesame is true for such terms as “beneath,” “below,” “lower,” “above,”“upper,” and the like.

For example, it will be understood that the spatially relative terms maybe intended to encompass different orientations of the device in use oroperation in addition to the orientation depicted in the figures. Forexample, if the device illustrated in the figures is turned over,elements described as “below” or “beneath” other elements would then beoriented “above” the other elements. Thus, the exemplary term “below”can encompass both an orientation of above and below. The device may beotherwise oriented (rotated 90 degrees or at other orientations) and thespatially relative descriptors used herein should be interpretedaccordingly.

The term “connect” and variations thereof (e.g., connected orconnection) may be direct or indirect. As used herein, the term “and/or”includes any and all combinations of one or more of the associated listitems.

FIG. 1 is a diagram illustrating a device 100 in which conceptsdescribed herein may be implemented. As illustrated, device 100 may be,for example, a network device that includes a multi-slot chassis 105employing a midplane design. Multi-slot chassis 105 may have a generallyrectilinear configuration with a front face 110, a rear face 115, and aside face 125. Baffles 120 may be located proximate to rear face 115.Baffles 120 may include a calibrated perforation density to regulateairflow within device 100. A matrix of fans 130 may be located proximateto side face 125 that may be used to cool device 100.

In accordance with this architecture, a single fan system may cool bothhorizontally oriented PCBs 135 and vertically oriented PCBs 140 ofdevice 100. For example, horizontally oriented PCBs 135 may be proximateto front face 110 and vertically oriented PCBs 140 may be proximate torear face 115. Additionally, as will be described below, baffles 120 mayprovide for an even distribution of airflow within device 100.

As a result of the foregoing, a single fan system having baffles toregulate air flow may adequately cool a device and PCBs associatedtherewith. That is, unlike other implementations that may require a fansystem (not illustrated) proximate to rear face 115 to cool PCBs 140 andanother fan system proximate to side face 125 to cool PCBs 135, a singlefan system 130 may cool PCBs 135 and PCBs 140. The concepts describedherein have been partially described in connection to FIG. 1.Accordingly, variations to the above will be described below.

EXEMPLARY DEVICE

FIG. 2 is a diagram illustrating an exemplary device 200 that mayoperate according to the concepts described herein. As illustrated,device 200 may include, among other components, a chassis 205, a frontface 210, a rear face 215, a side face 220, a side face 225, PCBs 230,PCBs 235, a midplane 240, baffles 245, and a fan tray assembly 250.

Chassis 205 may be any housing structure to support components of device200. In one implementation, chassis 205 may have a rectilinearconfiguration and may be made of, for example, metal, plastic, etc.Chassis 205 may include slots and/or guides (not illustrated) forreceiving and housing a plurality of modules, such as PCBs. As will bedescribed below, in one implementation, the slots and/or guides mayreceive and house PCBs oriented in a horizontal and vertical fashion inaccordance with a midplane design. That is, chassis 205 may be dividedinto a front compartment 207 and a rear compartment 209 by a transversemidplane, such as midplane 240. The size and/or dimensions of chassis205 may be based on the size and number of PCBs to be housed.

Chassis 205 may include front face 210, rear face 215, side face 220,and side face 225. Proximate to front face 210, device 200 may includePCBs 230 oriented in a horizontal fashion, and proximate to rear face215, device 200 may include PCBs 235 oriented in a vertical fashion.PCBs 230 and PCBs 235 may each include an array of PCBs, where each PCBis substantially parallel to another PCB within the array.

Midplane 240 may be any connector for mating one or more PCBs of PCBs230 with one or more other components, such as one or more PCBs of PCBs235. Midplane 240 may be oriented orthogonal to both PCBs 230 and PCBs235. Midplane 240 may connect to a power supply (not illustrated).Midplane 240 may permit communication between one or more PCBs 230 andone or more PCBs 235.

Baffles 245 may include a structure to regulate airflow within a device.For example, baffles 245 may be metal plates each having a calibratedperforation density to regulate airflow proximate to PCBs 235. Forexample, airflow may be regulated based on baffles 245 being positionedand oriented in such a way to create an obstruction to prevent highvelocity airflow build-up and minimize re-circulating zones of airflowproximate to PCBs 235. As illustrated in FIG. 2, in one implementation,one baffle of baffles 245 may reside below PCBs 235 and another baffleof baffles 245 may reside above PCBs 235. Baffles 245 may be orthogonalto PCBs 235. FIG. 3 is a diagram illustrating an exemplary baffle 245.As illustrated, baffle 245 may include multiple holes 305 to regulateairflow. The size, shape, number, and arrangement of holes 305 depictedin FIG. 3 are exemplary. A perforation density associated with holes 305may be calibrated.

For example, baffles 245 may include round holes whose diameters may bevaried from 0.140″ to 0.500″ patterned in such a way to maximize thepercentage of opening (e.g., 60% or more). In certain areas, such asconnector area, where no airflow is required, the perforation may beignored so that the airflow may be concentrated to other areas.

Fan tray assembly 250 may include a frame having a matrix of fans tocool device 200. As illustrated, in one implementation, fan trayassembly 250 may be proximate to side face 220. For example, fan trayassembly 250 may be orthogonal to PCBs 230. Fans of fan tray assembly250 may pull air out and/or circulate air to cool device 200.

Although FIG. 2 illustrates an exemplary device 200, in otherimplementations fewer, additional, or different components may beutilized. For example, in other implementations, PCBs 230 could be in arear compartment 209 of device 200 and PCBs 235 could be in a frontcompartment 207 of device 200. Additionally, or alternatively, fans offan tray assembly 250 may push air to cool device 200.

FIG. 4 is a diagram illustrating an exemplary airflow pattern associatedwith the concepts described herein. In FIG. 4, device 200 is illustratedfrom a left side, frontal view. Airflows are illustrated by arrows thatcorrespond to a direction of airflow. An airflow illustrated in FIG. 4may be based on, for example, fan tray assembly 250, air pressuredifferences, chimney effect, etc.

As illustrated, airflow 410 may enter device 200 through an opening 405of front face 210. For example, opening 405 may be a vented portion ofdevice 200 to permit air to enter device 200. Airflow 410 may traversealong a bottom face 415 of device 200 toward rear face 215. Thereafter,airflow 410 may travel upward as airflow 420. As will be furtherillustrated and described in connection to FIG. 5, airflow 420 maytravel through baffles 245 while cooling PCBs 235. Thereafter, airflow430 may travel along a plenum existing between a top face 425 of device200 and PCBs 230. Finally, airflow 435 may travel toward fan trayassembly 250 of side face 220 to exit device 200 while cooling PCBs 230.

Although FIG. 4 illustrates an exemplary airflow pattern, in otherinstances, the airflow pattern may include additional and/or differentairflows.

FIG. 5 is a diagram illustrating a partial airflow pattern from aperspective of side 220 that may correspond to the concepts describedherein. As previously described, airflow 410 may enter from front face210 of device 200 toward rear face 215. Airflow 420 may move upwardthrough baffles 245 to cool PCBs 235. Based on baffles 245 and theirrespective perforation density, airflow 420 may be evenly distributed inthe rear of device 200. For example, baffles 245 may regulate airflow420 to minimize high velocity build-up and/or minimize a re-circulatingzone that may have a low velocity epicenter.

Although FIG. 5 illustrates an exemplary airflow pattern, in otherinstances, the airflow pattern may include additional, and/or differentairflows.

FIG. 6 is a flow diagram illustrating a process that may be associatedwith the concepts described herein.

Process 600 may begin with an airflow having a first direction beingreceived via an opening of a device (Block 610). For example, airflow410 may be received via opening 405. Airflow 410 may travel in a firstdirection, such as a direction from front face 210 to rear face 215.

The airflow may be redirected to a second direction that is orthogonalto the first direction (block 620). For example, airflow 420 may bedirected to a second direction that is orthogonal to the direction ofairflow 410, as illustrated in FIGS. 4 and 5. The redirected airflow 420may cool one or more electrical circuits of device 200, such as one ormore electrical circuits having a first orientation. For example,airflow 420 may cool one or more electrical circuits, such as PCBs 235that have a vertical orientation. In one implementation, airflow 420 maytravel in the second direction via baffles 245. That is, baffles 245 mayredirect airflow 420 upwards.

The airflow may be redirected to a third direction that is orthogonal tothe second direction (block 630). For example, airflow 430 may bedirected to a third direction that is orthogonal to the direction ofairflow 420. For example, the third direction may correspond to adirection from rear face 215 to front face 210, as illustrated in FIG.4.

The airflow may be redirected to a fourth direction that is orthogonalto the third direction (block 640). For example, airflow 435 may bedirected to a fourth direction that is orthogonal to the direction ofairflow 430, as illustrated in FIG. 4. The fourth direction maycorrespond to a direction from side face 225 to side face 220. Theredirected airflow 435 may cool one or more electrical circuits ofdevice 200, such as one or more electrical circuits that have a secondorientation that is orthogonal to the first orientation. For example,airflow 435 may cool one or more electrical circuits, such as PCBs 230that have a horizontal orientation.

In block 650, the airflow may then exit the device. For example, airflow435 may exit device 200 via fan tray assembly 250 based on fan trayassembly pulling air from device 200. For example, fans of fan trayassembly 250 may pull air from device 200 in a direction correspondingto airflow 435.

Although FIG. 6 illustrates an exemplary process, in other instances,process 600 may include fewer, additional, and/or different operations.For example, the airflows described may travel differently if, forexample, fan tray assembly 250 pushes air instead of pulling air.Additionally, or alternatively, the description of directions inrelation to faces of device 200 may be different. For example, if PCBs230 were in a rear compartment 209 of chassis 205 and PCBs 235 were in afront compartment 207 of chassis 205, airflow 410 may travel in adirection from rear face 215 to front face 210, and the remainingairflows may travel in a manner corresponding to that described above.

CONCLUSION

The foregoing description of implementations provides an illustration,but is not intended to be exhaustive or to limit the implementations tothe precise form disclosed. Modifications and variations are possible inlight of the above teachings or may be acquired from practice of theteachings.

In addition, while a series of blocks has been described with regard tothe process illustrated in FIG. 6, the order of the blocks may bemodified in other implementations. Further, non-dependent blocks may beperformed in parallel. Further, it may be possible to omit blocks withinthe process of FIG. 6.

Even though particular combination of features are recited in the claimsand/or disclosed in the specification, these combinations are notintended to limit the invention. In fact, many of these features may becombined in ways not specifically recited in the claims and/or disclosedin the specification.

No element, block, or instruction used in the present application shouldbe construed as critical or essential to the implementations describedherein unless explicitly described as such. Also, as used herein, thearticle “a” is intended to include one or more items. Where only oneitem is intended, the term “one” or similar language is used. Further,the phrase “based on” is intended to mean “based, at least in part, on”unless explicitly stated otherwise.

1. A chassis, comprising: a front section that contains a firstelectronic circuit board oriented in a first plane; a rear section thatcontains a second electronic circuit board oriented in a second plane,where the first plane and the second plane are substantially orthogonal;a midplane dividing the front and the rear sections; and a fan trayassembly including a plurality of fans to: provide a first portion of anairflow, having a first direction, from which a second portion of theairflow, having a second direction that is orthogonal to the firstdirection, is provided, cool, using the second portion of the airflow,the first electronic circuit board of the front section, provide, fromthe second portion of the airflow, a third portion of the airflow havinga third direction that is orthogonal to the second direction, where thethird direction is opposite the first direction, provide, from the thirdportion of the airflow, a fourth portion of the airflow having a fourthdirection that is orthogonal to the first direction, the seconddirection, and the third direction, and cool, using the fourth portionof the airflow, the second electronic circuit board of the rear section,where the fan tray assembly is oriented on a third plane that issubstantially parallel to the second plane.
 2. The chassis of claim 1,where the first plane is oriented horizontally and the second plane isoriented vertically, and the third plane is substantially orthogonal tothe first plane.
 3. The chassis of claim 2, where the fan tray assemblypulls the airflow to cool the front section and exhausts the airflowfrom the chassis.
 4. The chassis of claim 1, further comprising: abaffle including perforations to regulate one or more of the portions ofthe airflow.
 5. The chassis of claim 4, where the rear section containsthe baffle and the baffle is oriented substantially orthogonal to thesecond electronic circuit board.
 6. The chassis of claim 5, where thebaffle includes a plurality of baffles, the plurality of bafflesincludes a first baffle located above the second electronic circuitboard and a second baffle located below the second electronic circuitboard.
 7. The chassis of claim 1, where the fan tray assembly cools thefirst electronic circuit board by pulling the second portion of theairflow in a direction parallel to the first plane.
 8. The chassis ofclaim 1, where the fan tray assembly is oriented on the third plane ofthe front section.
 9. A method for cooling a device having a midplane,the method comprising: directing a first portion of an airflow, having afirst direction, to provide a second portion of the airflow having asecond direction, the second direction being orthogonal to the firstdirection; cooling, via the second portion of the airflow, a firstelectronic circuit board of the device, the first electronic circuitboard being orthogonal to the midplane; redirecting the second portionof the airflow to provide a third portion of the airflow having a thirddirection, the third direction being orthogonal to the second direction;redirecting the third portion of the airflow to provide a fourth portionof the airflow having a fourth direction; and cooling, via the fourthportion of the airflow, a second electronic circuit board of the device,the second electronic board being orthogonal to the first electroniccircuit board, where the first direction and the third direction areopposite directions, and the fourth direction is orthogonal to the firstdirection, the second direction, and the third direction.
 10. The methodof claim 9, where the directing comprises: directing the second portionof the airflow via a first baffle.
 11. The method of claim 10, where thedirecting further comprises: directing the second portion of the airflowvia a second baffle.
 12. The method of claim 9, further comprising:pulling the fourth portion of the airflow from the device using a fantray assembly; and causing the fourth portion of the airflow to exit thedevice.
 13. The method of claim 9, further comprising: receiving thefirst portion of the airflow via an opening located below the midplane.14. The method of claim 9, where the redirecting the second portion ofthe airflow: redirecting the second portion of the airflow at a locationthat is above the midplane.
 15. A device, comprising: a first pluralityof circuit boards oriented in a horizontal direction; a second pluralityof circuit boards oriented in a vertical direction; a verticallyoriented midplane providing a connection between one or more circuitboards of the first plurality of circuit boards and one or more circuitboards of the second plurality of circuit boards; and a fan system,oriented on a plane that is parallel to the second plurality of circuitboards, to: provide a first portion of an airflow, having a firstdirection, from which a second portion of the airflow, having a seconddirection that is orthogonal to the first direction, is provided, cool,using the second portion of the airflow, the first plurality of circuitboards, provide, from the second portion of the airflow, a third portionof the airflow having a third direction that is orthogonal to the seconddirection, where the third direction is opposite the first direction,provide, from the third portion of the airflow, a fourth portion of theairflow having a fourth direction that is orthogonal to the firstdirection, the second direction, and the third direction, and cool,using the fourth portion of the airflow, the second plurality of circuitboards.
 16. The device of claim 15, further comprising: a first baffle;and a second baffle, where the first baffle and the second baffleinclude one or more perforations to regulate at least the fourth portionof the airflow.
 17. The device of claim 16, where the first baffle isparallel to the second baffle.
 18. A device, comprising: a midplaneconnecting a first circuit board oriented orthogonal to a second circuitboard; a chassis; and a cooling mechanism oriented on a planecorresponding to a side of the chassis, where the cooling mechanismpulls air to: provide a first portion of an airflow, having a firstdirection, from which a second portion of the airflow, having a seconddirection that is orthogonal to the first direction, is provided, cool,using the second portion of the airflow, the first circuit board,provide, from the second portion of the airflow, a third portion of theairflow having a third direction that is orthogonal to the seconddirection, where the third direction is opposite the first direction,provide, from the third portion of the airflow, a fourth portion of theairflow having a fourth direction that is orthogonal to the firstdirection, the second direction, and the third direction, and cool,using the fourth portion of the airflow, the second circuit board, theplane being substantially parallel to the second circuit board.
 19. Thedevice of claim 18, where the chassis is compartmentalized into a frontsection and a rear section, and the cooling mechanism is oriented on theplane corresponding to the side of the chassis of the front section.